Half-life Values Research Articles

Computer-Aided Targeted Mutagenesis of Thermoclostridium caenicola d-Allulose 3-Epimerase for Improved Thermostability.

d-Allulose 3-epimerase (DAEase) is a key enzyme in d-allulose bioproduction. DAEase from Thermoclostridium caenicola suffers from poor thermostability, hampering its large-scale applications in industry. In this study, mutants A70P, G107P, F155Y, and D162T with increased melting point temperature (Tm) were obtained by targeted mutagenesis based on the calculation of the free energy of folding. The optimal single-point mutant G107P showed 11.08 h, 5, and 5.70 °C increases in the values of half-life (t1/2) at 60 °C, the optimum temperature (Topt), and Tm, respectively. Beneficial mutations were combined by ordered recombination mutagenesis, and the combinational mutant Var3 (G107P/F155Y/D162T/A70P) was generated with ΔTopt of 10 °C and ΔTm of 12.25 °C. Its t1/2 value at 65 °C was more than 140 times higher than that of the wild-type enzyme. Molecular dynamics simulations and homology modeling analysis indicated that the enhanced overall rigidity, increased hydrogen bonds between subunits, and redistributed surface electrostatic charges might be responsible for the improved thermostability of the mutant Var3.

Pharmacokinetics of HupA-PLGA-NPs of different sizes in the mouse blood and brain determined by LC-MS/MS.

Huperzine A, which was extracted from a Chinese herb, is a reversible and selective inhibitor of acetylcholinesterase (AChE), which is used as an anti-Alzheimer's drug that exerts evident pretreatment effects against exposure to organophosphate chemical warfare agents or pesticides. The aims of this study were to establish an LC-MS/MS method for the detection of HupA in biological samples and to investigate the pharmacokinetics of HupA polylactic-co-glycolic acid nanoparticles (HupA-PLGA-NPs) with different diameters in mice. The proposed LC-MS/MS method was established by optimizing the MS conditions and validating the specificity, linear range, lower limit, precision, accuracy, matrix effects, absolute recovery, and sample stability of the method. ICR mice were divided into three treatment groups: the HupA control group, the 46.4-nm HupA-PLGA-NP group and the 208.5-nm HupA-PLGA-NP group. All the mice in the three groups were administered 0.5 mg/kg HupA via the tail vein. The pharmacokinetic parameters in plasma and the brain were detected by LC-MS/MS. Pharmacokinetic parameters were analyzed using PKS pharmacokinetic software, and the relative bioavailability and brain-targeted drug targeting efficiency (DTE) were also calculated. The distributions of HupA-PLGA-NP groups showed marked changes compared with that of HupA in mice in vivo, and the particle size of nanodrugs exerted a significant effect on the pharmacokinetic parameters in mice. The half-life (T1/2) values in plasma of the 46.4- and 208.5-nm HupA-PLGA-NPs were 1.53- and 1.96-fold longer than that of the HupA at the same dose. The bioavailabilities of the two nanoparticles were 1.93- and 2.19-fold higher than that of HupA, respectively. In the brain, the Tmax values of the two HupA-PLGA-NPs of different sizes was 1.25 h, which was clearly longer than that of HupA (0.5 h), and the corresponding T1/2 values were 12.53 h and 8.47 h, which were 1.82- and 1.23-fold higher than that of HupA (6.89 h). In addition, the brain targeting index of the 46.40-nm HupA-PLGA-NPs was 1.48, which revealed an evident brain-targeting effect. The LC-MS/MS method has the advantages of good specificity, high sensitivity and needing a low sample amount and is economical and particularly suitable for determining the drug content in plasma and brain samples. The NP size is associated with the distribution patterns of nanodrugs. Therefore, a particular NP size can be selected to maximize the pharmacodynamics effects and control the toxicity of nanodrugs.

Studies on the pharmacokinetics of piperacillin/tazobactam in renal replacement therapy in patients with chronic renal failure


 
 
 
 Purpose: To study the pharmacokinetics of piperacillin/tazobactam in renal replacement therapy (CRRT) in patients with chronic renal failure (CRF).
 Methods: Six CRF patients treated with CRRT in the First Affiliated Hospital of Hebei North University from April 2020 to July 2020 were selected and administered 4 g of piperacillin and 0.5 g of tazobactam within 30 min after, and at 5, 30, 45, 60, 90, 120, 180, 240, 360 and 480 min after CRRT. The DAS software was used to calculate pharmacokinetic parameters while linear regression was used to analyze the relationship among patient characteristics, CRRT parameters, and pharmacokinetics.
 Results: The Cmax of piperacillin and tazobactam was 118.46 (96.12 - 161.12) mg/L and 27.45 (14.75 - 28.45) mg/L, while the volume of distribution (Vd) was 1.16 (0.72 - 1.59) L/h and 0.72 (0.57 -0.82) L/kg, respectively. The value for elimination half-life (t1/2) was 4.66 (3.19 -8.45) h and 4.25 (3.42 - 5.96) h, while total clearance (CL) was 7.28 (5.58 - 9.73) L/h and 6.37 (4.28 - 10.04) L/h, respectively. Multivariate linear regression showed that piperacillin Cmax was negatively correlated with the flow velocity of the substitution fluid (β = -0.679, 95 % CI = -0.278 - 0.943, p < 0.001). Piperacillin CL was positively correlated with the flow velocity of the waste liquid (β = 0.956, 95 % CI = 1.267 - 4.796, p < 0.001).
 Conclusion: When used in CRF patients receiving CRRT, piperacillin and tazobactam show decrease in Cmax and CL, but increase in t1/2. This finding should provide useful guidance for clinicians concerned.
 
 
 

Sensitive and rapid simultaneous quantitation of leucovorin and its major active metabolite 5-methyl-tetrahydrofolate in human plasma using a liquid chromatography coupled with triple quadruple mass spectrometry.

Bioanalysis of an endogenous compound such as leucovorin is never an easy task on a liquid chromatography tandem mass spectrometer (LC-MSMS). Unless it is necessary, regulatory guidance discourages working with surrogate matrices for calibration curve standard preparation. Herein, a selective and sensitive liquid chromatography-tandem mass spectrometry method for simultaneous determination of leucovorin and 5-methyl tetrahydrofolic acid in human plasma was developed and validated. Stable labeled internal standards, i.e. leucovorin D4 and 5- methyl tetrahydrofolic acid 13 C5 , were used as internal standards to track and compensate the parent compounds during processing and extraction from plasma. The method involves a rapid solid-phase extraction from plasma followed by reverse-phase gradient chromatography and mass spectrometry detection with a total run time of 5min. The method was developed and validated from 5 to 2,202 ng/ml for leucovorin and from 5 to 1,300 ng/ml for 5-methyl tetrahydrofolic acid. The mean recoveries for leucovorin and 5-methyl tetrahydrofolic acid were 100.4 and 100.9% respectively. The validated method enabled the simultaneous analysis of leucovorin and 5-methyl tetrahydrofolic acid in samples from clinical pharmacokinetic studies of leucovorin. The peak concentrations of leucovorin and 5-methyl tetrahydrofolic acid were 651-883 and 518-635ng/ml, respectively, in fasted and fed conditions. The terminal half-life values for leucovorin and 5-methyl tetrahydrofolic acid were 9.3-10.5 and 9.2-17.6h, respectively.

Assessment of Pharmacokinetic Parameters of Daidzein-Containing Nanosuspension and Nanoemulsion Formulations After Oral Administration to Rats

Daidzein has several biological effects such as antioxidation, anti-inflammation, chemoprevention, and anticancer effects.The aim of this study was to evaluate the impact of nano-formulations (nanoemulsion-NE and nanosuspension-NS) prepared to increase the oral bioavailability of daidzein, a poorly water-soluble isoflavone, on the pharmacokinetic parameters of daidzein in rats. A high-performance liquid chromatography-ultraviolet (HPLC-UV) method was successfully developed for daidzein analysis in rat plasma.The pharmacokinetics studies of the nano-sized formulations, compared to coarse daidzein suspension, were carried out in the rats by a single oral dose at 10 mg/kg (n=6/group). Area under the plasma concentration-time curve from time zero to extrapolation to time infinity (AUC0-∞), maximum plasma concentration (Cmax), time to reach maximum plasma concentration (tmax), andelimination half life (t1/2)values for coarse daidzein suspension, daidzein-NS, and daidzein-NE were estimated by a non-compartmental analysis. The AUC values of daidzein-NE and daidzein-NS were approximately 2.62 and 2.65 times higher than that of coarse daidzein suspension, respectively (p<0.05). Relative bioavailability (Frel) (%) values of daidzein following oral administration of nanosuspension or nanoemulsion formulations were about 265.6% and 262.3%, respectively. It revealed that nanoscale size is an important factor to overcome any dissolution rate barriers to oral bioavailability of the low water-soluble compound. Nanoemulsion and nanosuspension formulations are beneficial dosage forms to increase the oral bioavailability of Biopharmaceutical Classification System (BCS) Class II and Class IV compounds.

Monitoring the Persistence of Devrinol, Diazinon, and Trifluralin Residues in Soil Following Application of Organic Amendments

Pesticides have the potential mobility from the site of application to natural water resources leading to surface water quality problems. Binding pesticides to soil lead to immobilization preventing their mobility into surface water and enhancing their availability for degradation by soil microorganisms and their secreting enzymes. The impact of low-cost organic amendments used in agricultural operations on the persistence of three pesticides; devrinol, diazinon, and trifluralin in agricultural soil was investigated. Pesticide residues in sewage sludge (SS), farm compost (Comp), and no-mulch (NM) control treatment following field application were monitored at different time intervals using solvent partitioning and gas chromatographic procedure (GC). Half-life (T_1/2) values of the three pesticides in soil were determined under three farming practices to investigate how long each pesticide remains in each soil treatment. Results revealed the retention of devrinol by 30%, diazinon by 55%, and trifluralin by 80% in soil amended with SS compared to sole NM soil used as control treatment. This practice might prevent the off-site movement of pesticides. Devrinol T_1/2 value of 14.1 days was significantly (P≤ 0.05) lower in soil amended with Comp compared to SS amended soil due to its high dissipation constant (K). Diazinon residues fluctuated during the first week after spraying and started to decline, reaching a minimum value of 0.004 µg g^-1 soil at 35 days after spraying. Its T_1/2 value of 10.6 days was significantly lower in SS amended soil compared to Comp waste and control treatments (15.8 and 18.5 days, respectively). Trifluralin residues in NM soil showed a low dissipation constant and greater (T_1/2) value of 116 days. Its dissipation and degradation in soil amended with Comp and SS indicated half-life (T_1/2) values of 48.5 and 34.6 days, respectively. The low adsorptive capacity of devrinol due to its high-water solubility requires minimizing its application rates in agricultural regions to prevent environmental contamination of natural water resources.

Persistence of Trifloxystrobin and Tebuconazole in Cowpea Following Application of Combination Formulation

A supervised field trial of was conducted to estimate the residues of trifloxystrobin, its metabolite CGA 321113 and tebuconazole in cowpea after application of Nativo WG (trifloxystrobin 25% + tebuconazole 50%) @ 350 and 700 g ha−1. After last application, green pods were collected separately at different time intervals and processed following QuEChERS methodology. Residues of trifloxystrobin and tebuconazole were quantified by gas liquid chromatography and gas chromatography-mass spectrometry, respectively. The residues were found to be below LOQ (<0.05 mg kg−1) at 5 and 7 days for trifloxystrobin, and 10 days for tebuconazole, respectively, for recommended and double the recommended doses. The half-life values on green pods were 1.07 and 1.13 days for trifloxystrobin and 1.30 and 1.29 days for tebuconazole. A waiting period of 1 day should be followed for consumption of immature pods.

Berberis crataegina DC. as a novel natural food colorant source: ultrasound-assisted extraction optimization using response surface methodology and thermal stability studies

This study aimed to investigate the potential use of anthocyanin of Berberis crataegina DC. as a natural food coloring agent in the food industry. For this aim, the ultrasound-assisted extraction (UAE) method was performed to extract anthocyanin of Berberis crataegina DC. The effect of ultrasound power (X1: 20-100%), extraction temperature (X2: 20-60 °C), and time (X3: 10-20 min) on TPC and TAC of Berberis crataegina DC. extracts were examined and optimized by applying the Box–Behnken experimental design (BBD) with the response surface methodology (RSM). The influence of three independent variables and their combinatorial interactions on TPC and TAC were investigated by the quadratic models (R2: 0.9638&0.9892 and adj R2:0.9171&0.9654, respectively). The optimum conditions were determined as the amplitude level of 98%, the temperature of 57.41 °C, and extraction time of 13.86 min. The main anthocyanin compounds were identified, namely, Delphinidin-3-O-galactoside, Cyanidin-3-O-glucoside, Cyanidin-3-O-rutinoside, Petunidin-3-O-glucoside, Pelargonidin-3-O-glucoside, and Peonidin-3-O-glucoside. The anthocyanin degradation showed first-order kinetic, degradation rate constant (k), the half-life values (t1/2), and loss (%) were significantly affected by different temperatures (P < 0.05). Higher degradation (k) in anthocyanin content was observed at 90 °C. This study suggested that UAE is an efficient method for the extraction of TPC and TAC from Berberis crataegina DC.

Protection of antioxidants in pitaya (Hylocereus undatus) peel: effects of blanching conditions on polyphenoloxidase, peroxidase and antioxidant activities

Pitaya peel is a by-product of the fruit processing, rich in phytochemicals and has great potential for application in food industry. In this study, blanching was applied to the pitaya peel treatment for inactivation of the polyphenoloxidase (PPO) and peroxidase (POD) which caused the antioxidant loss in the material during the processing and preservation. The effects of blanching temperature and time on the PPO and POD activities as well as the stability of betacyanins and phenolics of pitaya peel were investigated. At the blanching temperature of 98 ± 2 oC, the inactivation rate constants and half-life values of PPO and POD were 6.6 × 10-3.s-1 and 105 s and 16.6 × 10-3.s-1 and 42 s, respectively. During the blanching, betacyanins and phenolics were partially destroyed, their degradation rate constants and half-life values were 9.3 × 10-4.s-1 and 744 s and 3 × 10-4.s-1 and 2310 s, respectively. During the storage of dried pitaya peel powder (PPP), the degradation rate constants of betacyanins and phenolics of the blanched PPP were 1.4 and 1.8 times, respectively lower than those of the unblanched PPP. In addition, reduction in DPPH radical scavenging and ferric reducing antioxidant power of the blanched PPP was significantly lower than that of the unblanched PPP.

Determination of the Stability and Intracellular (Intra-Nuclear) Targeting and Recruitment of Pre-HAC1 mRNA in the Saccharomyces cerevisiae During the Activation of UPR.

Nuclear degradation of pre-HAC1 mRNA and itssubsequent targeting plays a vital role in the activation as well as attenuation of Unfolded Protein Response (UPR) in Saccharomyces cerevisiae. Accurate measurement of the degradation of precursor HAC1 mRNA therefore appears vital to determine the phase of activation or attenuation of this important intracellular signaling pathway. Typically, pre-HAC1 mRNA degradation is measured by the transcription shut-off experiment in which RNA Polymerase II transcription is inhibited by a potent transcription inhibitor to prevent the de novo synthesis of all Polymerase II transcripts followed by the measurement of the steady-state levels of a specific (e.g., pre-HAC1) mRNA at different times after the inhibition of the transcription. The rate of the decay is subsequentlydetermined from the slope of the decay curve and is expressed as half-life (T1/2). Estimation of the half-life values and comparison of this parameter determined under different physiological cues (such as in absence or presence of redox/ER/heat stress) gives a good estimate of the stability of the mRNA under these conditions and helps gaining an insight into the mechanism of the biological process such as activation or attenuation of UPR.Intra-nuclear targeting of the pre-HAC1 mRNA from the site of its transcription to the site of non-canonical splicing, where the kinase-endonuclease Ire1p clusters into the oligomeric structures constitutes an importantaspectof the activation of Unfolded Protein Response pathway. These oligomeric structures are detectable as the Ire1p foci/spot in distinct locations across the nuclear-ER membrane under confocal micrograph using immunofluorescence procedure. Extent of the targeting of the pre-HAC1 mRNA is measurable in a quantified manner by co-expressing fluorescent-labeled pre-HAC1 mRNA and Ire1p protein followed by estimating their co-localization using FACS (Fluorescence-Activated Cell Sorter) analysis. Here, we describe detailed protocol of both determination of intra-nuclear decay rate and targeting-frequency of pre-HAC1 mRNA that were optimized in our laboratory.

A comparison of the threshold concentrations of DCD, DMPP and nitrapyrin to reduce urinary nitrogen nitrification rates on pasture soils – a laboratory study

Context Using nitrification inhibitors (NIs) for the targeted management of urine patches, to reduce nitrous oxide (N2O) emissions, requires determining the threshold concentrations of the NIs in urine for effective nitrification inhibition. Aims This study comparatively assessed the threshold concentrations of three NIs: dicyandiamide (DCD), 3,4-dimethylpyrazole phosphate (DMPP) and 2-chloro-6-(trichloromethyl) pyridine (nitrapyrin) to reduce urinary nitrogen (N) nitrification rates on two contrasting pasture soils. Methods Four rates of each NI (3–27 mg DCD kg−1 soil, 1–13 mg DMPP kg−1 soil and 1–14 mg nitrapyrin kg−1 soil) were added to urine-amended soils and incubated at laboratory room temperature. The amended soils were sampled periodically to monitor changes in mineral-N concentrations. Key results The threshold concentration of DCD (3 mg kg−1 soil, lowest rate tested) was lower than that of nitrapyrin (5–7 mg kg−1 soil) and DMPP (13 mg kg−1 soil, highest rate tested) on both soils. Greater NI effectiveness corresponded to greater NI persistence, with higher (P &lt; 0.05) half-life values observed for DCD (16 ± 2 days, mean ± s.e.) compared with nitrapyrin (10 ± 2 days) and DMPP (9.2 ± 0.3 days). All three NIs persisted longer (P &lt; 0.05) with higher application rates. Conclusions Compared with DCD and nitrapyrin, a higher DMPP concentration was required to effectively inhibit urinary N nitrification rates in the pasture soils. Implications Choosing the ideal application rate of NIs to inhibit nitrification under field condition, and hence mitigate N2O emissions from urine patches, requires consideration of the factors that affect NI loss.

Generalized multi-scale kinetic model for data-driven modelling: Mangifera pajang antioxidant degradation in choline chloride/ascorbic acid natural deep eutectic solvent

This paper formalizes a new multi-scale kinetic model for a process influenced by several limiting factors which are multi-scale in nature. The multi-scale kinetic model incorporates all of the dominant factors which can be expressed in the form of first-order kinetics where some of the factors could have delayed effects on the process. The applicability of this new model is demonstrated using a case study of Mangifera pajang antioxidant degradation modelling. The results show that the multi-scale kinetic model can provide improved modelling accuracy, with a Root Mean Square Error (RMSE) of 1.32%. Interestingly, the analysis of the multi-scale model suggests the presence of two groups of antioxidant compounds based on the degradation dynamics in the M. pajang extract. The dominant group of antioxidant compounds contributes about 87% to the total antioxidant concentration, and the degradation of this group is much slower than the non-dominant antioxidant compounds at pH 3. At a high temperature above 60 °C and pH above 7, the fast-degrading group of antioxidants becomes dominant in the extract. Significantly, the proposed multi-scale kinetic model is generic and flexible which can be applied to data-driven modelling of many different processes. • New generalized multi-scale kinetic model for improved modelling accuracy. • Antioxidant degradation modelling over broad range of experimental conditions. • Reveals two groups of antioxidants in the extract. • Provides more accurate half-life value of antioxidants.

Update of the BIPM comparison BIPM.RI(II)-K1.Sn-113 of activity measurements of the radionuclide 113Sn to include the 2017 result of the LNE-LNHB (France)

Main textSince 1975, 7 laboratories have submitted 13 samples of 113Sn to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.Sn-113. Recently, the LNE-LNHB (France) participated in the comparison and the key comparison reference value (KCRV) has been updated to take account of the change of the 113Sn half-life value used for the SIR. The degrees of equivalence between each equivalent activity measured in the SIR and the updated KCRV have been calculated and the results are given in the form of a table. A graphical presentation is also given.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Enabling biocatalysis in high-concentration organic cosolvent by enzyme gate engineering.

Biocatalysis in high-concentration organic solvents (OSs) offers many advantages, but realizing this process remains a huge challenge. An R-selective ω-amine transaminase variant (AcATAM2 ) exhibited high activity toward 50 g/L pro-sitagliptin ketone 1-[1-piperidinyl]-4-[2,4,5-trifluorophenyl]-1,3-butanedione (PTfpB). However, AcATAM2 displayed unsatisfactory organic-cosolvent resistance against high-concentration dimethyl sulfoxide (DMSO), which is required to enhance the solubility of the hydrophobic substrate PTfpB. Located in the substrate-binding tunnel, enzyme gates are structural elements that undergo reversible conformational transitions, thus affecting the accessibility of the binding pocket to solvent molecules. Depending on the conformation of the enzyme gates, one can define an open or closed conformation on which the enzyme activity in OSs may depend. To enhance the DMSO resistance of AcATAM2 , we identified the beneficial residues at the "enzyme gate" region via computational analysis, alanine scanning, and site-saturation mutagenesis. Two beneficial variants, namely, AcATAM2F56D and AcATAM2F56V , not only displayed improved enzyme activity but also exhibited enhanced DMSO resistance (the half-life value increased from 25.71 to 42.49 h under 60% DMSO). Molecular dynamic simulations revealed that the increase in DMSO resistance was mainly caused by the decrease in the number of DMSO molecules in the substrate-binding pocket. Moreover, in the kilogram-scale experiment, the conversion of 80 g/L substrate was increased from 50% (AcATAM2 ) to 85% (M2F56D in 40% DMSO) with a high e.e. of >99% within 24 h.

Theoretical studies on two-proton radioactivity

The Coulomb and proximity potential model for deformed nuclei (CPPMDN) have been used to compute half-lives of two-proton ($2p$) radioactivity of $^{6}\mathrm{Be}$, $^{12}\mathrm{O}$, $^{16}\mathrm{Ne}$, $^{19}\mathrm{Mg}$, $^{45}\mathrm{Fe}$, $^{48}\mathrm{Ni}$, $^{54}\mathrm{Zn}$, and $^{67}\mathrm{Kr}$, and the values are compared with the experimental data. The predicted half-life values are also compared with six theoretical models and two empirical formulas. The standard deviation is least for the model CPPMDN ($\ensuremath{\sigma}=1.03$), compared to other theoretical models and formulas, which indicates that CPPMDN is the apt model for studying $2p$ radioactivity. I extended the model to predict half-lives of other 15 even-Z nuclei for which $2p$ radioactivity is energetically possible with released energy, ${Q}_{2p}&gt;0$, and hope that the predictions may serve as a guide for future experimental investigations. The observed linear nature of the new Geiger-Nuttall plot of ${log}_{10}[{T}_{1/2}(s)]$ computed using CPPMDN versus $({Z}_{d}^{0.8}{\ensuremath{\ell}}^{0.25}){Q}_{2p}^{\ensuremath{-}1/2}$, stresses the reliability of the model in predicting $2p$ radioactivity half-lives.

Assessing the influence of pig slurry pH on the degradation of selected antibiotic compounds

Veterinary medicines are routinely used in animal husbandry and the environment may consequently be exposed to them via manure applications. This presents potential environmental and societal risks such as toxicological effects to aquatic/terrestrial organisms and the spread of antimicrobial resistance. Regulatory studies that assess the degradability of veterinary antibiotics during manure storage currently permit the use of just one manure per animal type although we speculate that heterogenic properties such as pH could be driving significant variability within degradation rates. To bridge this knowledge gap and assess degradation variability with pH, laboratory degradation studies were performed on a broad range of antibiotics (ceftiofur, florfenicol, oxytetracycline, sulfamethoxazole and tylosin) at three different environmentally relevant pH levels (5.5, 7, and 8.5). The effect of pig slurry pH on degradation rates was found to be significant and compound specific. Usually, acidic slurries were found to inhibit degradation when compared to neutral pH, for florfenicol, tylosin, and ceftiofur; the associated changes in DT50 (half-life) values were 2–209 h, 35.28–234 h, and 0.98–2.13 h, respectively. In some circumstances alkaline slurries were observed to enhance the degradation rate when compared to those for neutral pH, for tylosin, the respective changes in DT50 values were from 3.52 to 35.28 h. Comparatively, the degradation of sulfamethoxazole was enhanced by acidic conditions compared to neutral (DT50 20.6–31.6 h). Tentative identification of unknown transformation products (TPs) was achieved for sulfamethoxazole and florfenicol for the first time in pig slurries. These results reveal the importance of considering slurry pH when assessing the degradation of antibiotic compounds, which has implications for the acidification of manures and the environmental risk assessment for veterinary medicines.Environmental relevance and significance: Given the significant effect of pig slurry pH on degradation rates, manure degradation studies need to be harmonised and standardized, taking into account the influence of pH.

A Randomized, Double-Blind, Placebo-Controlled, First-in-Human Clinical Trial to Assess Safety, Tolerability, and Pharmacokinetics of LY-CovMab, a Potent Human Neutralizing Antibody Against SARS-CoV-2.

IntroductionWe aimed to evaluate the safety, tolerability, pharmacokinetics, and immunogenicity of a single dose of LY-CovMab in Chinese healthy adults.MethodsWe conducted a phase 1, randomized, dose-escalation, placebo-controlled trial in 42 volunteers, 18–45 years of age, and 40 out of 42 received a single dose of LY-CovMab or placebo with LY-CovMab at a dose of 30 mg, 150 mg, 600 mg, 1200 mg, and 2400 mg. There were ten subjects in each group receiving LY-CovMab or placebo in a 4:1 ratio with the exception that the 30 mg group had two subjects both receiving LY-CovMab.ResultsAmong the 42 randomized participants, 40 received an injection with 32 administered LY-CovMab and 8 administered placebo. A total of 18 drug-related treatment-emergent adverse events (TEAEs) were reported in 12 subjects (30.0%), including protein urine present (25%, 10/40) and blood creatinine increased (7.5%, 3/40). The incidence of drug-related TEAE in each dosage group was as follows: 150 mg (28.6%, 2/7), 600 mg (25%, 2/8), 1200 mg (14.3%, 1/7), 2400 mg (50%, 4/8), and placebo (37.5%, 3/8). All drug-related TEAEs were grade 1, and most of them were recovering/resolving or recovered/resolved without taking action. The serum exposure of LY-CovMab (Cmax, AUC0–last, AUC0–inf) after intravenous infusion increased in an approximately proportional manner as the dose increased from 150 to 2400 mg. The elimination half-life (t1/2) value did not differ among different dose cohorts and was estimated to be around 28.5 days.ConclusionsA single dose of LY-CovMab was shown to be safe and well tolerated in Chinese healthy adults. The pharmacokinetic (PK) profiles of LY-CovMab in healthy adults showed typical monoclonal antibody distribution and elimination characteristics. LY-CovMab demonstrated dose proportionality.Trial RegistrationClinicalTrial.gov Identifier NCT04973735.Supplementary InformationThe online version contains supplementary material available at 10.1007/s40121-021-00572-x.

Development and Validation of Reversed-Phase HPLC Method for the Determination of Epirubicin and Its Application to the Pharmacokinetic Study of Epirubicin Loaded Polymeric Nanoparticle Formulations in Rats.

Epirubicin, commonly used as anticancer drug for various types of tumors like breast, liver, lung, stomach, ovaries, and bladder for its improved antitumor efficacy and safety. A rapid, sensitive, and reliable bioanalytical method was developed and validated for epirubicin using conventional reverse phase HPLC with UV detection. The developed method was successfully applied to investigate the pharmacokinetics of epirubicin after intravenous administration of a reference epirubicin and its designed nano-formulations to rats. C18 column was used in an isocratic mode for analyte elution at a flow rate of 1.0 mL/min with UV detection of 234 nm. The mobile phase was composed of acetonitrile 22% (channel A) and 0.025% tri fluoro-acetic acid in water (channel B). Ondansetron was added as an internal standard, and the plasma samples were analyzed after protein precipitation. A concentration range of 0.016-1.024 μg/mL was selected for the construction of calibration curves, with LLOQ of 0.016 μg/mL. Results showed that the value of AUC, half-life, and mean residence time of designed nano-formulation were bounce to 10, 9, and 11 times higher, when compared to the reference epirubicin after intravenous dose of 10 mg/kg of epirubicin to rats, respectively. The designed epirubicin nano-formulations achieved clinically significant pharmacokinetic values in rats. Current method will help epirubicin future research using clinical samples and drug bioequivalence studies on various novel formulations for drug safety purposes.

Improvement of extraction and stability of anthocyanins, the natural red pigment from roselle calyces using supercritical carbon dioxide extraction

In this work, anthocyanins, a natural red pigment, were isolated from roselle calyces using supercritical carbon dioxide (SC-CO2). Three process conditions, namely pressure, temperature, and co-solvent ratio (ethanol-water), were investigated using a three-factorial design from response surface methodology (RSM). The method was used to model the extraction of anthocyanins, total phenolic content, total flavonoid content, and colour characteristics (i.e., lightness (L*), chroma (C*), and hue (h°)). The best conditions were 27MPa, 58 °C, and 8.86 % co-solvent ratio at maximal anthocyanin, phenolic, and flavonoid content, with minimal L* and C* values. The anthocyanin production was 1197 mg/100 g of dried roselle calyces. Next, the high relative value of cyanidin 3-sambubioside and phenolic compound in SC-CO2 extract was analyzed using an ultra-high-performance liquid chromatogram (UHPLC). Anthocyanins stored at 4 °C, 25 °C, and 37 °C had average reaction rate (k) and half-life (t1/2) values of 0.0032 and 216 days, 0.0098 and 70 days, and 0.024 and 28 days for SC-CO2 and 0.0093 and 74 days, 0.0222 and 31 days, and 0.0444 and 15 days for solid-liquid extraction (SLE), respectively, in first-order degradation kinetics. These findings demonstrated that the studied conditions using SC-CO2 provided lower degradation rates and a longer t1/2 than the conventional SLE methods.

1119. Assessment of Vancomycin Pharmacokinetic Parameters in Pediatric Patients After Liver Transplantation

BackgroundVancomycin is largely prescribed to treat gram-positive bacterial infections in pediatric patients after liver transplantation with the same empirical doses prescribed in other critical conditions due to the absence of pharmacokinetic studies in this population. The objective of this investigation was to describe the vancomycin pharmacokinetic parameters and to assess the vancomycin percentage of target attainment with empirical regimen.MethodsProspective and longitudinal study with pediatric post-liver transplantation patients who received at least 48 hours of vancomycin between January 2020 and May 2021. Patients with acute or chronic renal failure or receiving renal replacement therapy were excluded. Vancomycin therapy started with 40-60mg/kg daily, one-hour infusion. The pharmacokinetic parameters were determined by one-compartment model with first-order kinetics using near steady-state postdistributional peak and trough within the same dosing interval. Therapeutic target was defined as vancomycin 24-hour area under the curve/minimum inhibitory concentration (AUCss0-24/MIC) ≥ 400 and < 600. The study protocol was approved by the local ethics committee.ResultsWe included 18 sets of peak/trough serum concentrations obtained from 12 patients. The patients had median age of 11 (interquartile range [IQ] 8-16) months. The found vancomycin clearance, volume of distribution and half-life values were, respectively, 2.1 (IQ 1.4-2.8) mL/kg/min, 0.6 (IQ 0.5-0.7) L/kg and 3.2 (IQ 2.3-4.0) hours. After the initial dose regimen, 5 (42%) patients reached the therapeutic target.ConclusionUsing the one-compartment model, we evaluate the pharmacokinetic parameters of vancomycin in pediatric patients after liver transplantation. Most of patients did not reach the therapeutic target with empirical regimen, so it is prudent to monitor the exposure to vancomycin directly by AUC/MIC ratio to maximize antimicrobial efficacy.Disclosures All Authors: No reported disclosures